Theory of quadrupolar sunspots and the active region of August, 1972

  title={Theory of quadrupolar sunspots and the active region of August, 1972},
  author={Hai-shou Yang and H. Chang and J. Harvey},
  journal={Solar Physics},
Energy is stored when the force-free magnetic field in an active region departs from a potential field, the departure showing up as a shear in the field. As soon as the field untwists, energy will be released to produce flares. Based on this idea, we derived an analytical solution of the equation of force-free field under the assumption of a constant force-free factor, and found expressions for seven important quantities for quadrupolar sunspots: the magnetic energy of the twisted field, that… Expand
3 Citations
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